Trend of storm water runoff pollutants temporal variability from different land use sites in Korea

Pollutants temporal variability during storm water runoff is of great concern due to diffuse pollution source, rainfall change, impervious cover percentage, soil permeability and runoff volumes. This study examines the variations and fluctuations of storm water pollutants during runoff duration from different land use sites in Yongin city, Korea. Samples from urban, agriculture, construction, mix catchment, and stream sites location were collected and analyzed. Concentration profiles, correlations between storm variables and event mean concentration, flow weighted mean concentration (FWMC) levels and pollutant loading curves were calculated to characterize the pattern of storm water temporal variability. It was found that pollutants level varied significantly between the monitoring sites and also differed temporally from individual events within same location. The magnitude of suspended solids (SS), chemical oxygen demand (COD), and total phosphorous (TP) showed high variability in mix catchment, urban and stream sites, whereas, chloride (Cl) showed minimal variability in all sites. Average values of FWMC level were found high in 2 to 4 h or >4 h of runoff duration from mix catchment and construction sites which clearly show the non-existence of first flush effect. These findings can support for the improvement of storm water monitoring projects in Korea.